The Residue And Hydrolysis Of Moroxydine Hydrochloride And Its Effect On Soil Enzyme In Tobacco Field

In order to study how the residue of moroxydine hydrochloride digest in tobacco soil, explore how different factors affect moroxydine hydrochloride hydrolyze, and study how moroxydine hydrochloride affect three kinds of common enzymes in tobacco soil, this thesis, by adding a recovery experiment research and establishing technical methods to analyze and test the residue of moroxydine hydrochloride in tobacco field soil, fresh tobacco leaves and flue-cured tobacco leaves, on the basis of field experiment, using a more systematic study to test the application of 20% moroxydine hydrochloride Wettable Powders, and the residue of its active ingredient moroxydine hydrochloride's digestion and regularity in tobacco soil. In addition, by laboratory simulated experiments, this thesis presents a more detailed study of the influence of moroxydine hydrochloride on the main factors that affect hydrolysis (pH, temperature, and three typical clay minerals). This thesis also studies how moroxydine hydrochloride affects the invertase, urease, and catalase activity in tobacco soil. These studies do not only provide scientific basis for the evaluation of impact of moroxydine hydrochloride on ecological environment, but also provide important basic data for rationally applying 20% moroxydine hydrochloride. The main contents and results of this paper are as follows:1. Establishing a highly-effective high performance liquid chromatography (HPLC) technological method to detect the residue of moroxydine hydrochloride in tobacco soil samples by adding a recycle experiment:using mixed solution of acetone-distilled water-saturated sodium chloride (14:1:1,v/v/v)asa extraction solvent of moroxydine hydrochloride in tobacco soil samples and-a mixed solution of methyl cyanide-distilled water (10:1, v/v) as a extraction solvent of moroxydine hydrochloride in fresh and post-cured tobacco leaf samples. When the added concentration is between 0.10?2.00mg/kg, the recovery of added moroxydine hydrochloride in tobacco soil, fresh tobacco leaves, and flue-cured tobacco leaves were 87.4%-89.6%,79.4%-82.5% and 82.2%-93.8% respectively, with the relative standard deviations of 5.7%-9.9%,6.8%-8.5% and 8.2%-12.3%. the minimum detected concentration of moroxydine hydrochloride in tobacco soil was 0.1mg/kg, and the minimum detected concentration of moroxydine hydrochloride in fresh tobacco leaves and flue-cured tobacco leaves was 0.1 Omg/kg. These results indicate that the analyzing and testing methods are in line with the technical requirements of pesticide residues analysis and detection.2. In 2013 and 2014, digestion experiments of 20% moroxydine hydrochloride Wettable Powders residues were carried out in Changsha, Hunan and Qingdao, Shandong. The results showed that the digestion dynamics of moroxydine hydrochloride in tobacco soils and fresh tobacco leaves were in line with first-order kinetics of chemical reactions, and the digestion half-life of moroxydine hydrochloride in tobacco soil and fresh tobacco leaves were 17.54d-28.88d and 11.23d?15.30d respectively. Therefore, moroxydine hydrochloride belongs to easy digestion pesticide in tobacco soil. Applying 20% moroxydine hydrochloride Wettable Powders, with a low dose of the drug amount 3000.0 g/ha (active ingredient dosage:600.0 g ai/ha) and a high dose of the drug amount 4500.0 g/ha (active ingredient dosage:900.0 g ai/ha) in tobacco soil four times and five times respectively as the ultimate residue test, the results showed that:the amount of moroxydine hydrochloride residue in tobacco soil is small, after 60d of application, the residue of moroxydine hydrochloride is ND-0.2813 mg/kg. The amount of moroxydine hydrochloride residue in flue-cured tobacco leaves is greater than that in the tobacco soil after the 60d application, its residue is ND?1.3673mg/kg. So, the reasonable recommendation for applying 20% moroxydine hydrochloride Wettable Powders in tobacco soil is:with the dosage of active ingredients 600 g ai/ha (200g dosage formulation/acre), controlling tobacco virus and disease, spraying up to four times, spraying interval 7 days, and 60 days for security interval.3. A preliminary study of the effect of aqueous solution pH value, temperature, and three typical clay minerals on the hydrolysis of moroxydine hydrochloride through laboratory simulation experiments. The results showed that:under different pH value conditions, the hydrolysis rate of moroxydine hydrochloride is different. Hydrolysis rates under alkaline conditions is faster that under neutral or acidic conditions; the hydrolysis rate of moroxydine hydrochloride is accelerated with increasing temperatures; after adding clay minerals, the hydrolysis rate of moroxydine hydrochloride did not significantly increase, but the amount of moroxydine hydrochloride in water content was greatly reduced.4. Studying the influence of moroxydine hydrochloride Wettable Powders on the activity of three soil enzymes: invertase, urease and catalase by conducting laboratory simulation experiments, in order to understand the possible effect of moroxydine hydrochloride Wettable Powders on the ecological system of tobacco soil. The results showed that:moroxydine hydrochloride's impact on invertase in soil is greater, showing an influence of activation, the higher the concentration, the more obvious of activation; moroxydine hydrochloride's impact on urease showed an activation and then inhibition, the potency and concentration were positively correlated; moroxydine hydrochloride's impact on catalase showed an inhibition performance, the maximal inhibition is on the 7th d, and thereafter the inhibition decreased, by the 20th d, the influence gradually returned to normal levels.